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TATES UNITE THOMAS C. ROCHE, OF BROOKLYN, ASSIGNOR TO E. & H. T. ANTHONY & C0,, OF NEW YORK, N. Y.

PHOTOGRAPHIC PAPER AND SENSlTIVE EMULSION THEREFOR.

SPECIFICATION forming part Of Letters Patent NO. 314,31 6, dated March 24, 1885.

Application filed March 18,1884. (X0 specimens.)

T0 ctZZ whom, it may concern Be it known that I, THOMAS 0. Boone, of Brooklyn, in the county of Kings and State of New York, have invented a new and useful Improvement in Photographic Paper and Sen sitive Emulsions Therefor, of which the fol lowing is a full, clear, and exact description.

This invention consists in the production,as anew article of manufacture, of a photographicprinting paper having a toothed facing of gelatine and bromide of silver; and it further includes a compound for facing. photographic paper consisting of gelatine, bromide of silver, and a suitable toothing substance, substantially as hereinafter described; likewise a combination, with a photographic emulsion of gelatine and bromide of silver, of a toothing substance, such as the sulphate of baryta.

Heretofore when a sheet of paper has been coated with a gelatine emulsion sensitized with a bromide of silver, the surface, when dry, has been smooth and incapable of having a tooth to receive and hold the mark of a crayon or pencil. By my invention, however, Iam enabled to obtain in a quick and simple manner a mat or roughened surface on gelatine'bromide paper suitable for positive photographicprint ing which shall have-tooth for touching or marking it with crayon, lead-pencil, pastels, &c., and this I do by directly mixing a suit able toothing substance with the gelatine emulsion sensitized with a bromide of silver, and then applying to the surface of the paper, in the usual or any suitable manner, said sensitive emulsion having the toothing substance, which is insoluble therein, incorporated with it. Thus I obtain in a quick and simple manner a mat or roughened surface on gelatinebromidepaper for positive photographic printing, so as to give tooth for touching or marking it with crayon, lead-pencil, pastels, &c., and am enabled to prepare a rapid printingpaper for enlarging purposes, either by the solar camera or other enlarging apparatus.

In carrying out my invention the gelatinobromide-of-silver compound I prefer to use is that described in Letters Patent No. 241,070, issued to me May 3, 1881, and which consists in first softening the gelatine in water and adding bromide of ammonia or an equivalent bromide in suitable proportions, say, about one hundred and ilfty grains of good gelatine, sixty grains of bromide of ammonia, and about five ounces of water, then dissolving the gelatine by heat and adding gradually nitrate of silver, say, about one hundred grains dissolved in about five ounces of water, then subjecting the whole'to a continued heat fortwoor three days, (more or less,) at about 80 to 100Fahrenheit, then, after allowing it to cool and set, cutting it into fragments and washing out the soluble n1atter, then melting it by heat and adding about its weight of water. To this or other like emulsion I then add for each four liquid ounces thereof about one tea-spoonful (more or less) of the insoluble toothing substance and thoroughlyincorporate the same therewith. To produce a very coarse-grained or toothed surface, double the quantity specified of the insoluble graining or toothing substance may be incorporated with the sensitive material or emulsion.

Different toothing substances insoluble in said emulsion might be used, including the sulphate of baryta, pumice-stone powder or emery powder of different grades, and the paper to which said sensitive emulsion is applied may either be sized or unsized, and said gelatinobromidc-of-silver emulsion having the insoluble toothin g substance incorporated with it may be applied to the surface of the paper on which the positive photographic printing is to be done in any suitable manner known to the arts for applying other orsimple emulsions.

If the graining or toothing substance used be sulphate of baryta, which gives a superior finish to the white portions of the picture, then said sulphate may be used in a wet state, as when used in a damp state it readily assimilates with a gelatine emulsion and is held in suspension therein. It might, however, be used in a dry state, in which case the proportion may be about one dram of sulphate of baryta to each ounce of the sensitive emulsion, first mixing it, however, in a weak solution of gelatine and water, and afterward mixing and incorporating it in any suitable manner'with the sensitive emulsion. Said sulphate of baryta will be held in suspension just as the bromide of silver is held, and does not affect the sensitiveness of the emulsion.

By incorporating an insoluble *graining or toothing' substance with the gelatine and bromide of silver I dispense with all special or mechanical means for producing a grained or toothed surface upon the paper, and by means of a gelatino-bromide-of-silver emulsion having a toothing substanceincorporated with it, as described, the usual method of producing a mat or roughened surface upon the paper by rubbing down the surface of the print with cuttie-fish bone and pumice-powder is dispensed with, and I am enabled to quickly prepare a surface superior in uniformity to that heretofore produced for the purposes specified.

From the foregoing description it will be seen that I have produced a sensitive photographic-printing paper having all the rapid printing and developing qualities of bromideof-silver paper with the added quality that the print when toned and finished in the ordinary manner has a roughened or tooth surface and may be then touched and worked by the pencil or crayon.

\Vhat I claim, and desire to secure by Letters Patent, is

1. As a new and useful or improved article of manufacture, a photographic-printing paper made with a toothed facing of gelatine and bromide of silver, as herein set forth.

2. The within-described compound for facing photographic paper, consisting of gelatine, o bromide of silver, and a suitable toothing substance, such as the sulphate of baryta, prepared in the manner and proportions substantially as described.

3. The combination, with a photographic 3 5 emulsion of gelatine and bromide of silver, of a toothing substance; such as the sulphate of i baryta, substantially as herein described.

THOMAS C. ROCHE. 

